MIMO Repeater Digital SIC for Full-Duplex C-Band Coverage

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Solution Overview

Problem

C-band frequencies experience high path loss and wall penetration loss, limiting the coverage of C-band fixed wireless access nodes, which are used as an alternative to fiber installations in 5G networks, especially in areas where wired infrastructure is limited or costly.

Innovation Solution

Implementing a multiple-input multiple-output (MIMO) repeater with digital self-interference cancellation (D-SIC) filters to subtract self-interference from RF signals, allowing for interference-free signal amplification and forwarding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If C-band frequencies are used for FWA, then higher data rates are achieved, but path loss and wall penetration loss increase, limiting coverage range

Engineering Contradiction:

Improvedata rateVSAvoidpath loss and wall penetration loss

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

A MIMO repeater is introduced as an intermediary device between the base station and the user equipment. The repeater receives the C-band signal, processes it through digital self-interference cancellation, and retransmits it to extend coverage. This mediator approach allows the system to overcome the inherent path loss and wall penetration loss of C-band frequencies without sacrificing data rate performance.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces traditional analog interference cancellation mechanisms with digital signal processing. By using digital self-interference cancellation (D-SIC), the system can more effectively model and subtract self-interference components, enabling the repeater to operate efficiently in C-band frequencies and extend coverage while maintaining high data rates.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Area of stationary object

If MIMO repeater with D-SIC is implemented, then self-interference is canceled and coverage is extended, but device complexity increases

Engineering Contradiction:

Improvecoverage areaVSAvoidrepeater structure complexity

Core Design Contradiction:

Area of stationary objectVSDevice complexity

Solution Approach 1:

The repeater is divided into multiple transceiver pairs, with each transceiver handling specific spatial components of the signal. The digital self-interference cancellation is performed independently for each transceiver pair, allowing the complex cancellation process to be segmented into manageable operations that can be parallelized and reduce overall system complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts filter coefficients and processing parameters based on the detected self-interference characteristics. By changing these parameters in response to actual interference conditions, the repeater can maintain effective cancellation while adapting to varying operational environments, thus managing complexity through intelligent parameter adaptation rather than fixed complex architecture.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If full duplex operation is used in MIMO repeater, then spectral efficiency is improved, but self-interference increases

Engineering Contradiction:

Improvespectral efficiencyVSAvoidself-interference

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful self-interference generated during full-duplex operation into a useful signal for cancellation. By using the detected self-interference to train and update the digital cancellation filters, the system turns the previously harmful interference into the key ingredient for effective cancellation, enabling full-duplex operation to proceed with high spectral efficiency while maintaining low residual interference.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The system implements a feedback mechanism where the detected self-interference is fed back into the digital self-interference cancellation process. This feedback loop continuously refines the cancellation filters based on actual interference conditions, allowing the repeater to maintain full-duplex operation with high spectral efficiency while dynamically adapting to changing interference patterns.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS20260019143A1Digital self-interference cancellation for MIMO repeater

Publication Date: 2026.01.15 SAMSUNG ELECTRONICS CO LTD

AI summary

A multiple-input, multiple-output (MIMO) repeater includes a plurality of transceiver pairs. Each transceiver pair includes a first transceiver configured to transmit and receive radio frequency (RF) signals to and from a base station (BS) via a first antenna, and a second transceiver configured to transmit and receive RF signals to and from at least one user equipment (UE) via a second antenna. The MIMO repeater also includes a processor operatively coupled to each transceiver of the plurality of transceiver pairs. The processor is configured to, for each transceiver pair: filter, via a self-interference cancellation (SIC) filter, an RF signal received from one of the first antenna or the second antenna; subtract an output of the SIC filter from the RF signal to generate a filtered RF signal; and transmit, via the other of the first antenna or the second antenna, the filtered RF signal.